Re: How can I keep or discard certain blocks of an XML file based on first line of block?

[Anonymous Monk]

Have a look at XML::Twig, especially the section "XML::Twig 101". That has code examples and should get you started on how to parse the XML file, select the elements to handle, and only print those that you want to the output.

As for parsing the date, here's one of several ways to do that, using the DateTime and DateTime::Format::Strptime modules.

use DateTime;
use DateTime::Format::Strptime;
my $strp = DateTime::Format::Strptime->new(on_error=>'croak',
    pattern => '%Y%m%d%H%M%S %z');
my $input = "20140623203000 -0400";
my $dt = $strp->parse_datetime($input);
print $dt->iso8601, "\n";
print "Weekday: ", $dt->day_of_week, " (", $dt->day_name, ")\n";

Another thing to note: In your description you talk about line-based parsing, which is a dangerous thing with XML. Many, many applications that work with XML don't consider some or all whitespace, including newlines, to be significant. That means that you may suddenly find two tags that were previously on two lines to show up on the same line, or have a tag and its attributes split over several lines, etc. That's one of the reasons XML should always be parsed with a real XML parser. Fortunately, there are lots available, with lots of different interfaces to suit different applications and different coding styles.